Tutorial: Introduction to GDAL
完了要件
2. Retrieving information from GIS data
2.2. Retrieve information from vector data
For retrieving info from vector data we use the ogrinfo command.
1. Execute the following command:ogrinfo
-al roads.shp | more <ENTER>
ogrinfo
-al gem_2011_gn1.shp | more <ENTER>
2. Answer these questions:
- What are the projections of these two shapefile?
- What are the EPSG codes?
As you can see there are several EPSG codes reported. That is because different elements of the projection have their own EPSG code. The rule of thumb is that you can take the last EPSG code. So the projection of
roads.shp
is EPSG: 4326,
which means that it is in Geographic Coordinate System (GCS) with coordinates in Latitude/Longitude.For
gem_2011_gn1.shp
the projection is EPSG: 28992, which is the Dutch projection (Amersfoort RD/New).More info about the ogrinfo command can be found here.